<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        .header {
            width: 100%;
            height: 60px;
            background-color: lightslategrey;
        }

        .left {
            width: 200px;
            background-color: lightseagreen;
            height: 600px;
        }

        .right {
            position: absolute;
            top: 60px;
            left: 200px;
            width: 1334px;
            height: 600px;
            background-color: lightgrey;
        }
    </style>
</head>

<body>
    <div class="header"></div>

    <div class="left"></div>
    <div class="right"></div>

</body>

</html>